NORTH AMERICAN GEOTRUPINAE — ^HOWDEN 275 



Coarse punctures usually confined to lateral portions and along 

 margins of the pronotum and sometimes in the vague median in- 

 dentation. Minute secondary punctures usually not evident. Scutel- 

 lum generally triangular, with sides slightly arcuate, more so anteriorly. 

 Elytra with well developed striae, which, dorsally at least, lack 

 punctures. Elytral margin narrow. 



Foretibia of male with anteriormost of the seven external teeth ex- 

 panded sharply inward and forward. Male also has tarsal claws of 

 mesothoracic legs greatly enlarged, similar to splendidus. Hind femur 

 of male without modifications, similar to female. Foretibia in both 

 sexes with longitudinal raised carina, similar to blackburnii, running 

 its entire length on the inner edge of the dorsal flattened surface. A 

 row of setae is closely adjacent to the base of this carina throughout 

 its length, being similar to the carina and setae of splendidus. Ex- 

 ternal face of tibia of meso- and metathoracic legs each with three 

 transverse carinae, the innermost sometimes poorly developed. Two 

 partial carinae are usually present on the tibia of the metathoracic 

 legs. 



The genital capsule and elongate genitalia well developed, the 

 dorsal parameres very distinctive (pi. 5, fig. 3). 



Variation in size and color within the species is considerable. 

 Otherwise the characteristics are rather constant, with no geographic 

 or consistent population differences noted. 



This species can most easily be distinguished by its dull green or 

 purple color, without any coarse punctures in elytral striae. Other 

 characteristics are the vague tubercles of the head, the carina of the 

 foretibia similar to blackburnii but with the setae adjacent to the 

 carina tliroughout its length rather than separated anteriorly (as it is 

 in blackburnii), the enlarged tarsal claw of the mesothoracic leg of 

 the male, and the distinctive genital armature of the male (pi. 5, 

 fig. 3). 



Geotrupes semiopacus Jekel occurs from southern Canada to the 

 mountains of North Carolina and Tennessee. Predominantly a com- 

 mon northern species, it is active the entire summer from May until 

 September. 



Many of the specimens examined bore in addition to the locality 

 label one reading "fungi." G. semiopacus has often been found in 

 wooded areas frequenting the same general type of habitat as balyi 

 or hornii. 



Besides its habit of feeding on fungi, Spector (1943, p. 229) found 

 semiopacus attracted to a heap of chicken heads and feathers placed 

 imder a flat rock. No other attractants were listed by Spector or 

 other authors. 



